Looks like Steam has the game for $44, and you get a copy of Darksiders for free! Darksiders is a very cool game, IMHO, but I've already played it, so I'm not so interested. However, you can give your copy to somebody else on Steam.

a bunch of different stores have different offers it looks like. Amazon has a better chainsword upgrade, Gamestop has Black Templars or Space Wolves armor options, I think someone else is offering a better quality bolter upgrade.

I'll probably be going through Gamestop as I have gift cards for them. Pity there is no Dark Angels armor option though.